This was my experience at Facebook. Attempting things with a small team (or heaven forbid by yourself) was heavily frowned upon because it didn't justify manager and director salaries. As a result you ended up with poorly performing over-engineered code bases that prefered complex, expensive systems that would take multiple teams to build, but for whatever reason complexity that would improve performance was frowned upon. I'm sure this is common at many big tech companies. I didn't work on the mainline FB app but it seemed like part of the culture.